Depends, If you are using Windows98 and did not empty the "Trash Bin" (and assuming you did not tell 98 to empty the trash immedately, to dump), you can simply go to the trash folder and recover the files. On the other hand if again assuming you are Windows98, there is an undelete application that can be used.
However; if it has been a while that since you trashed files. You might be able to recover parts of files.
How Windows deletes files is to literally put an * in front of the file name. This tells Windows this is okay the reuse the space this file once occupied. Now if you just trashed the files I would suggest geting an undelete app to recover the files.
What I do if I am not too sure about total deletion, I archive those files to a CD (CD's being so cheap, it is stupid not to archive, at 20 cents a CD in bulk) then delete them. Now it does not matter if they are totally gone.
Remember CD archive, no regrets later. Nuff said?