You must know that in case of any major problem with your hard disk, you must stop using it at all in write mode, at least the time necessary to understand what happens. Information there is very volatile...
If ever, one morning, awaking, you computer say "can't load, no system installed", you must not begin reinstalling all the stuff.
If you have windows installed, I can't promise you can recover your data, but it's likely you will recover all your Linux stuff, provided it's not located too low in the disk structure. This is because some windows viruses erases the very first disk cylinder, whatever is on. However I didn't ever experiment such virus and can't say for sure. Try recovering anyway.
You must also know that I give you all this information only for this -information purpose. Neither I nor any other people but you can be held responsible for any problem your data can have using this info. There are too many different systems on the world for anybody being able to promise anything. I can only wish you luck and hope you, like me, will be happy recovering data.