Backups do NOT Erase files ever, well if not done backwards?NO OS stated, how can any one help lacking that.TC4400 hard ware. ONLY !no boot, the HDD will not boot , unstated windows, or is it linux?>windows what.?sounds XP like to me... the book on your PC tells you to use restore to fix, bad loaders.startup repair its called, on mine its F11.on Vista back is F10. this key activates here is what came new.HP Compaq tc4400 Tablet PCit came with Windows 2000,XP or Vitstaits so old it has a SQUARE scree, 4:5 ratio.the carbon date is as old as, 2006It is still supported by HP due to it was made for all those years.and the 10 year clock is not timed out yet on support.sthe books are still on line and the drivers too.see these books>
https://support.hp.com/us-en/product/hp-compaq-tc4400-tablet-pc/1847962/manualsdoes BIOS work, press F10 at power on, see BIOS screensthis is first,then the BIOS then boots the HDD, C: boots.to repair a good HDD, startup one runs this.F11 is your hot key, for HP recovery /restore.page 188 here is the page (PDFPAGE) to read.http://h10032.www1.hp.com/ctg/Manual/c00692629the books says, on that page follow the onscreen instructionsit says that to cop out, as there are 3 OS used, here.each uses different screensI too cop out, not doing all 3 now for you.next time say what OS is there.on the bottom of said PCis a COA sticker on said sticker is the MS licenseclearly stating what OS is there. (was there day 1)but if someone upgraded this PC, then the sticker is a lie.oops but you killed the HDD totally dead of all partitions did you not? Sanitized, word, used.no name of disk used, my guess is MIL spec erase.