I have a weird problem: I have the SP1 file for WinXP (xpsp1a_en_x86.exe) burned on a CD-R as part of my backup. But when I try to install it from the CD-R (after a WinXP install), I get the message: "File is corrupt". Now, I have tried to burn it again several times using both Nero and EZCD, but there doesn't seem to be a problem with the burning itself (the CRC check is good). I have also tried copying the file to the hard drive first, but still no luck. I'm only able to install SP1 by downloading it again from Microsoft and installing. BTW, when I check the digital signature of the "corrupt" file, it says it's invalid, so maybe it got to do with some kind of a time limit, I don't know.
Maybe some of you had this problem when you tried to install SP1 from a backup, so maybe you could help. I just want to be able to backup the damn file, instead of downloading it (it's 125MB) everytime I do a clean WinXP install.