Why is my computer slow after a fresh format?

I had something corrupted on my hard-drive and couldn't install most software, including any anti-virus programs. I finally found a trial version online that would install, and discovered I had 26 viruses--after nearly a year without protection, it was no surprise. I still couldn't install hardly anything, so I saved all my pictures and files to my webpage, and reformatted the computer. I then installed Norton Antivirus, Microsoft office, and the usual games I've had on the last 3 computers I've owned. I installed all the Microsoft updates, and waited a month before downloading my pictures and files. I waited another month before I felt "safe". Its been almost 4 months now, and my computer is terribly slow. I have to reboot sometimes 3 times before it will run fast enough to open Explorer in less that 60 seconds. Then the speed is erratic. Sometimes it will be too slow to use in the evening, and then run ok in the morning without a reboot.

Why is my computer slow after a fresh format?house call

Ahhh ... where to begin? Well unfortunately as with most questions of this nature, we simply don't have enough facts to give the panacea that's so sought after. That being said, a few things come to mind ... a freshly formatted system shouldn't consume an abnormal amount of resources. Do you have a multi-function printer? (i.e., scanner - fax - printer) These are unbelievable CPU consumers. Previous mentions of pictures stored on the hard drive and defragmentation are unlikely culprits ... especially on a freshly formatted system. Spyware and viruses should be ruled out as well - for the same reason. These can't survive a drive reformat. It's entirely likely that your system may be too old to support what's being asked of it. What is the operating system? What is the CPU speed? How much RAM is there? Is your anti-virus running a start-up scan in background? Running Windows XP on any machine slower than 1GHz and less than 256MB of RAM is just asking for trouble. Even though Microsoft minimum recommendations are stated less this - they don't say that it will work but work slowwwwwwwwwwwly. Without more specifics, it's just too difficult to give an adequate recommendation. Good luck ...