Here's a few suggestions for a slow system. Here's what I do to keep things performing well.
I have XP home installed, with 2100+ AMD Athlon, K7T MB, 20GB drive, and 512MB RAM. I've tried every combination of tweaks and fixes and have my system as fast and stable as possible.
Routine regular maintenance (weekly):
1. Defrag hard drive. This can make a big difference.
2. Check the fragmentation report and make sure that the MFT file and Paging file are not fragmented, and if so, do boot time defrag (with something like Executive Software diskeeper)
3. Optimizing hard drive with Norton Speed Disk.
4. Clean registry with JV16 Power tool (available free at http://www.macecraft.com/index.php?lg=en&id=downloads). Norton Windoctor is another registry cleaner.
5. Get rid of any performance hitting spyware with AdAware http://lavasoft.element5.com/support/download/
6. Use this free tool (XP Prefetch clean and control http://www.jester2k.pwp.blueyonder.co.uk/jester2ksoftware.htm) to get rid of old large and potentially bogged down prefetch settings).
7. Remove old unwanted programs and/or very large files (movies etc) that you don't want.
6. Clean junk files using Window Washer (http://www.webroot.com/wb/products/windowwasher/index.php)
Excellent Tweaks to increase performance.
1. Install freshui for some good XP tweaks (http://www.freshdevices.com/freshui.html) This will enable you to quickly tweak things such as: Windows CPU Priority increase to Realtime; L2 Cache Optimization to match what your CPU L2 supports; I/O Memory Cache size increase from 4096 to 65536; Menu Reaction Delay to 0; Force Windows System Core to stay resident; and wfp (windows file protection) cache size drop to 50MB from it's original enormous value.
2. I've modified my XP sys.ini file and specified these lines:
PageBuffers=32
MinTimeSlice=15
DMABufferSize=64
ConservativeSwapfileUsage=1
you can research the net on what these settings will do for you.
3. Right click "my computer", "properties", "Advanced" Performance "settings", advanced tab, Processor Scheduling to Adjust for best performance "Programs"; memory usage best performance for "System cache". Under virtual memory set paging file to be a fixed number (mine is at 500 MB) so that less defragmentation occurs.
Another thing you can do is go into your BIOS and optimize settings for Advanced BIOS features and Advanced chipset features. A good BIOS guide is http://www.techspot.com/tweaks/bios/print.shtml
There's probably a few more I've done but I can't recall right now.
If you're hesitant about messing with settings like those above, rest assured that if you're System Restore is working or if you have Goback, any error is easily and quickly fixed. You won't know how your system will perform until you challenge it

I have XP home installed, with 2100+ AMD Athlon, K7T MB, 20GB drive, and 512MB RAM. I've tried every combination of tweaks and fixes and have my system as fast and stable as possible.
Routine regular maintenance (weekly):
1. Defrag hard drive. This can make a big difference.
2. Check the fragmentation report and make sure that the MFT file and Paging file are not fragmented, and if so, do boot time defrag (with something like Executive Software diskeeper)
3. Optimizing hard drive with Norton Speed Disk.
4. Clean registry with JV16 Power tool (available free at http://www.macecraft.com/index.php?lg=en&id=downloads). Norton Windoctor is another registry cleaner.
5. Get rid of any performance hitting spyware with AdAware http://lavasoft.element5.com/support/download/
6. Use this free tool (XP Prefetch clean and control http://www.jester2k.pwp.blueyonder.co.uk/jester2ksoftware.htm) to get rid of old large and potentially bogged down prefetch settings).
7. Remove old unwanted programs and/or very large files (movies etc) that you don't want.
6. Clean junk files using Window Washer (http://www.webroot.com/wb/products/windowwasher/index.php)
Excellent Tweaks to increase performance.
1. Install freshui for some good XP tweaks (http://www.freshdevices.com/freshui.html) This will enable you to quickly tweak things such as: Windows CPU Priority increase to Realtime; L2 Cache Optimization to match what your CPU L2 supports; I/O Memory Cache size increase from 4096 to 65536; Menu Reaction Delay to 0; Force Windows System Core to stay resident; and wfp (windows file protection) cache size drop to 50MB from it's original enormous value.
2. I've modified my XP sys.ini file and specified these lines:
PageBuffers=32
MinTimeSlice=15
DMABufferSize=64
ConservativeSwapfileUsage=1
you can research the net on what these settings will do for you.
3. Right click "my computer", "properties", "Advanced" Performance "settings", advanced tab, Processor Scheduling to Adjust for best performance "Programs"; memory usage best performance for "System cache". Under virtual memory set paging file to be a fixed number (mine is at 500 MB) so that less defragmentation occurs.
Another thing you can do is go into your BIOS and optimize settings for Advanced BIOS features and Advanced chipset features. A good BIOS guide is http://www.techspot.com/tweaks/bios/print.shtml
There's probably a few more I've done but I can't recall right now.
If you're hesitant about messing with settings like those above, rest assured that if you're System Restore is working or if you have Goback, any error is easily and quickly fixed. You won't know how your system will perform until you challenge it
