Today I got to troubleshoot two equally annoying problems, one caused by a virus and the other caused by AVG.
Starting with the virus, my customer had the infamous GALA Google re-director virus. What this one does is redirects any attempt to use Google to a web page from GALA that looks similar to Google's but is an obvious spoof.
The way to fix this is by left clicking on the arrow next to the magnifying glass and choosing "manage search engines"
Once there you'll need to delete your default search engine by defaulting another engine and then choosing your original one and deleting it. After that you'll need to close the window, click on the arrow next to the magnifying glass again and choose "find search providers"(or something to that effect). Choose your provider and re-install them. Doing this will remove the infected search engine and install a new clean one in its place.
My next customer had a problem with downloading files from IE/Firefox and downloading attachments from emails. "not enough disc space" was the common message, and if 200+GB of free space isn't enough for a single file, I don't know what is! The cause of this error is an anti virus program, since the program was denying the downloads the computer gave a default(and way off the mark) reason for the denied download.
The simple fix? remove any active anti virus software you have installed and find a new provider. My customer had AVG 8.5, after uninstalling that I was able to pull attachments from emails and download from IE8. From there I reinstalled AVG 9.0 and everything continued to work smoothly.