Welcome to Windows ME!
Seriously, here are a few ideas -
- make sure there are no hardware issues. RAM is adequate and not mismatched or faulty; drives are defragged and correctly configured with up-to-date drivers and settings; PCI, AGP, USB, etc. interfaces and drivers are installed correctly; graphics are working correctly and are properly set for his monitor, usage and memory; check power requirements for installed hardware and verify power supply is adequate (30% minimum margin of safety); and run some good hardware evaluation tests (memory, processor, graphics, etc.).
- make sure there are no software issues. Check running background and startup processes. Remove, disable or stop unnecessary background programs (AOL, Office, MSN, Norton, etc.). Run your malware scanners again. Check BIOS and verify all settings.
I'd also recommend a clean OS reinstallation, but you say this is not an option? Too bad, 'cause this can really improve things.
I'm sure there are countless other tips and tricks to improve performance. Google for them and you will be amazed.
If you need help or more info on any of the above, let us know.
Dell