I cant play my gamesaves qhen i want to pla...

Does the save location exist?
Make sure that these two files exist on your computer:
for GTA III
My Documents\GTA3 User Files
for GTA: VC
My Documents\GTA Vice City User Files

Have you tried downloading save files off the internet to check if it's the applications ability to read?
http://www.gtasavegames.com/savegames/gta_iii
http://www.gtasavegames.com/savegames/Vice_City

Also, check if your antivirus is blocking the application from reading the memory.

gta3 , I take it that you know how to save your levels ( by entreing wharehse/lift).
when re-loading game you must ask the game to load game pick as required- if you know this already it could be that the game did not load corretly and you may need to load it again ---
you can also save your game levels to disc and this will allow you to have them even if you have not got enough room on memory.
give it ago if no help - try mastertronics.com