and more tests;
I also think this is likely malware but try these;
1] Run IE in its Safe Mode configuration, (Start > All programs > Accessories > System Tools > "Internet Explorer (No Add-ons)".
This not only disables add-ons but also ActiveX and toolbars, so some pages may not display properly. But the test is to see if logos now display the right way up.
2] If 1 above doesn't work, reboot the OS into it's Safe Mode options, select "Safe Mode with networking", and open IE in that mode and test.
If any malware is installed, it may not get the chance to run in Safe Mode and so this is another test to see if logos display properly.
That said, if you download and install CCleaner from http://www.piriform.com/ccleaner and run its analysis with Stock Settings, (no need to change anything on the application's opening page), then run the cleaner, that will remove all TIF files, and will delete history and cookies, as well as any Temp folder files, so if there are any corrupted internet files, that might clear it. All cookies will be deleted, including any held in Chrome, so if your customer needs any for logins etc, head over to Options > Cookies before the run to save them. But personally I would get rid of them all.
I would also download, install, run, update then run a full scan of SUPERAnti-spyware, (SAS), from SUPERAntiSpyware.