The computer I'm using to post this has some problems. I'm think maybe the motherboard is bad. The problems are it's very slow to boot up. If you try to restart it may take 10 minutes or so to reboot or it may not reboot at all unless you turn power off and then repower.At times it runs very slow. It also freezes up more than usual. I've had viruses on this computer before and this is acting differently than a virus. Also it has been having these problems for 10 months or so. I think if it was a virus it would have progressed from this point.
Is it possible to change out the motherboard without affecting the memory etc? Also was wondering the cost of a motherboard. Any advice on what the problem would be or steps to trouble shoot my problem?

How long has it been since the hard drive was reformatted and operating system installed? It does not sound like a motherboard issue. It could be a virus. Some sit dormant until activated by some source, then can really bog down your system.

Ditto on the not MB.
This Windows XP?
Take a look in 'Control Panel' , 'Administrative Tools' , 'Event Viewer' ,'System'.
See if anything shows an error.
You might try running some anti-spyware programs to clear out any unwanted 'stuff'.
http://www.safer-networking.org/index2.html
http://www.malwarebytes.org/

Yes it is WindowsXP. I have Spybot installed and run it fairly regularly. Last couple times I times I ran it it reported zero issues. I'll check control panel.

Okay I went into control panel and made my way to event viewer. Event Viewer was broken down to 4 catagories. Application error records/security audit records/system error records/custom log error records. The first three have hundreds of events. The custom log error record has nothing. Is there something specific to look for in the event viewer? If there is something significant present what can I do to rectify it?

Look for any events under Application with a white "X" on red background with Error as the type - especially events that have errors corresponding to the times you boot your PC.

Mine seemed to be slowing down at boot time as well and after checking the Application log it showed a lot of successive disk read errors, indicating to me there was a growing number of bad blocks on the drive it was trying to access at startup time.

I wound up replacing my hard drive and cloning the old information to the new - Seagate supplied a CD program to do this with the new drive saving me having to reinstall all my software and configuring it all.

These logs are normally set to a particular file size and then begin writing over itself. Here's something you might do. Insure you have the particular log highlighted in the left window pane then select Action > Clear All Events then NO if you want to save the data. Once the events are cleared, reboot your machine and check the logs again. This will give you a good idea of what is really current and what's happening at boot-up time.