Runaway process or virus??

[chend]

For the last two weeks, my sony vaio (xp home) laptop has slowed down to very slow speeds. at first i thought it was related to a belkin wifi card used at the motel, but it continued when i went to nyc. the task manager shows that system idle process is taking from 20-94% cpu. i would rather not reformat and start over, but if i need to i will. i use symantec antivirus, spybot, adaware. recently used registry cleaner, but only after i came back from my trip. any hints, help? tia
don.

[RickDev]

Well, you have done everything I would have done. Is the anto-virus scheduled to scan your drive on a daily basis, and if so, do you let it finish scanning? Look for the process Rtvscan.exe and make sure it is not running all the time. When I say running, I mean using more than a few % of process all the time.

[superpod]

Just some basic stuff tht u've probably done, but try clearing ur startup list, keep only the AV and firewall. Also check the HDD condition, disk fragmentation levels. Maybe u an run a disk cleanup, chkdsk and defragment the drive for performance improvemnt. Have u tried that a well?