Whenever the PC "Isn't acting Right" - check the Event Logs and make
sure no Errors are being logged. If so, you should resolve them.
Next on the list is Malware.... check Malke's removal page for help on
that topic:
http://elephantboycomputers.com/page2.html#Removing_Malware
58 Processes is a little high, but it all depends on the software and the
hardware in your machine. Natively, XP is going to have around 30+
processes active. Startups & Watchdogs are something of a problem,
as they are constantly active and using resources. Removing them is a
judgment call - Do you really need them. Media players tend to have
a "Me, Me - choose Me" type of attitude.
For general performance, I'd run an PCPitStop Benchmark. It can give
you comparison values for your PC against similar hardware. The score
isn't as important as whether you have any "Flagged" categories.