To begin with, My friends bought a notebook Acer Aspire 5520 with Vista on it, after some time they wanted to have XP on it, ok, XP was installed (not by me).. some time later(guess what?) they wanted their vista back... Factory default parameters consisted of two partitions C and D(and hidden pqservice of cource) with preinstalled Vista on C. XP was installed to D, and of cource ALT+F10 stopped to work, because MBR was overwritten by XP. The easiest way is just to restore Vista's MBR and after that ALT+F10 should work. in my case it worked too, but vista didnt want to restore, just black screen after ACER logo... So, the next steps will help u to restore your Vista to factory defaults.
A-(for those, installed another version of Vista, XP, etc, in other words, if u have bootable OS, but ALT+F10 does not want to work)
1) Get this http://rapidshare.com/files/147429369/Acer.zip.html
this zip consists of 4 files, acer.bat, script which restores mbr, MBRWRWIN.EXE the utility for resotring mbr, rtmbr.bin (mbr itself) *THIS TRMBR.BIN IS ONLY FOR ACER ASPIRE 5920,IN NEXT STEPS WE WILL GET RTMBR FOR YOUR NOTEBOOK*, cmd.exe(console, you won't need it)
2) Next, you will need a software that can browse hidden partitions, i took Acronis True Image Suite 10(try to get the same, do not take 11, i don like it =) )
3) If we use Acronis first we have to create backup of our pqservice partition. Open Acronis and follow:
On the right press "Backup", press next, choose "My computer" press next, choose pqservice(*IF YOU HAVE A PARTITION CALLED NTFS YOU SHOULD BACKUP IT EITHER*) press next, pop-up windwos will appear press OK, choose where you want ot save the backup press next, choose Create a full new backup archive press next, choose Set the options manually press next, go to Compression level and choose maximum, go to Archive splitting and choose "Fixed size, bla bla bla" in open list choose 4,7Gb DVD format press next, press next, press proceed,wait, press ok =)
3)Now we have to take that file to restore mbr for our notebook
4)In Acronis True Image follow:
Tools-Explore BackUp Archive. Choose on the left the location where you have saved your backup =) You will see two files PQservice1 and PQservice2, it is ok, choose PQservice1, and press Open. mbr file you need is located in RYTOOLS and is called RTMBR.BIN. take(i mean RMB, copy)this, not RTMBR2.BIN =)
5)now extract our zip to C:\Acer and overwrite the file rtmbr.bin with the one that you have copied...(be carefull the default rtmbr.bin is for aspire 5920)
6)start acer.bat, thats all, restart you notebook, ALT+F10 works...