Virtual memory is RAM, not your hard drive space, so deleting files won’t help it.
To augment the proper RAM in your computer, Windows also sets aside a portion of the hard drive to act as RAM (paging file). Of course this is much slower than actual RAM, but necessary.
So to increase your "virtual memory", either buy more RAM and install it into the computer, increase your paging file as detailed above, or:
press windows key+r
-> type in msconfig into "run" box
-> go to the "startup" tab
-> Anything that your not sure why it’s there, give the process name a Google and disable it if you don’t see anything saying it’s essential.
This will mean less programs are running all the time in the background, they all use up virtual memory.
Generally, you want your paging file to be 2/3 of the amount of proper RAM in your system, but if that’s too little, just increase until it isn’t