My desktop PC is suddenly taking a lot longer to complete its start-up sequence, and the only way it will connect to the internet is if I do the "diagnose and repair" option for the network. Then it looks like it gets a new IP address and works just fine. Sometimes if doesn't even work when I do that. The only thing I've done recently was run Pruran Defrag. The longer start-up time began shortly after that. I have McAfee installed and it hasn't found malware, and neither did the Kaspersky online scan. I have noticed that McAfee processes seem to be taking up a lot of resources, specifically mcshield.exe and McSvHost.exe.
My desktop is running Vista SP2, has a 2.10 GHz AMD Phenom 8459 Triple-Core Processor with 4GB of RAM.
Thanks for any help.