corrupt

I bought 2 800 MB CDs. One local and one Amkette, but when I insert them into the computer it says that they are 703 MB. I have tried reading them at 2 other (friend's) places. 1. Liteon combo 2. LG CDRW 3. Samsung CDRW and in software... 1. Nero 6 2. Roxio easy cd & dvd creator 6 3...

well while browsing the DVD..i found out bout it....and on clicking on it it asks place to extract the files....but after d/l 7/8MB out of 400odd MB..it starts giving error ....Broken Files...i have tryed to extract it using WinRAR ...but no use..same error there also..so is the Installation...

i want to install windows 98 but my pc has windows xp. if i install windows 98 it will corrupt my windows xp. Is there a way to install windows 98 after windows xp. kindly Help me.

plz tell me some recovery software through which i can boot into my system & recover files if my windows become corrupt or something like that.... it'll be good if it has Graphics interface...