Old XP new XP Problems with Folders

Since my OS&Mobo were seriously fucked up, I've put in a new HDD and installed a fresh new copy of Windows XP Pro SP2 on it.
Problem is: I forgot to make Backups of my old personal folders and some other folders who I just can't get any access to.
Booting the old WinXP is impossible, since a major part of it was overwritten/killed in the process of XP Pro SP2 install.
What now? D:

If your motherboard was fucked up how the hell did you install an OS? As for your problem the solution should be obvious.