Well like most good geeks, I searched 1st, the 2 posts I found were either out dated or for a mac. Also a wake up call for doing things late at night after a long day at work. I clicked before reading GRRRR.
Right so I have delete a file, too large for recycle bin, in fact the file is the "image" back up of my laptop stored on my home PC should I ever need to do a restore. I create an image every few months, rename them by date, so I have a recovery point. I went to delete the most recent image as I had got that "security essentials" virus (another story ) But I deleted the wrong image file. I have search the net and there are LOTS of file recovery programs, I am willing to part with the $$ but want one that works so..... recommendations and maybe personal experiance. 
Setup, windows7 ultimate 32bit, file store on a seperate drive (750Gb)  D: (data only )  file is a windows backup image approx 2.2Gb in size. No work has been done on the PC since deleted.