Over the past month my computer seems to be generating small application files (61k)with various names;
bcapj.exe
bdklvvk.exe
bedooj.exe
bhsl.exe
bibtzvdhita.exe
etc,
an then placing them in my windows/system32 directory. It then modifies my startup registry to run these applications. I keep deleting both the files and the startup script, but they continue to return. I have run spybot and McAfee virus scan but does not fix he problem. My conmputer also seems to run slow, especially whne accessing the hard drive. Any suggestions?

Use HiJackThis to track down or check for possible infections.
Here is all the the info needed to empower yourself, anything you are not sure of, put into a search engine like Google.
Read this link 1st, it has step by step.
http://www.wilderssecurity.com/show...
Important: Create a specific folder on your hard drive called HijackThis to keep its backups.
You can do this by going to My Computer (Windows key+e) then double click on C: then right click and select New then Folder and name it HijackThis. Download and unzip HijackThis.exe into this folder.
http://www.merijn.org/downloads.html Or, http://tomcoyote.com/hjt/ Or, http://www.spywareinfo.com/~merijn/...
If possible run HJT in Normal mode ( not Safe ) with all your normal startup's working.
HijackThis Tutorial - How to Analyse your own log.
http://spywarewarrior.com/viewtopic...
http://hometown.aol.co.uk/jrmc137/h...
http://www.bleepingcomputer.com/tut...
http://www.malwarehelp.org/understa...
HijackThis log file analysis ( online )
http://hijackthis.de/index.php?lang...
Or,
http://startup.networktechs.com/pag...
http://hjt.iamnotageek.com
Malware Prevention: Prevent Re-infection
http://wiki.castlecops.com/Malware_...
http://www.offroaders.com/ralphtheg...

pat122261, google those files and see how they can be removed, it's a good place to start

Hopefully my advice will help you...Please post back with your results....thanks