Reparing my boot sector

Hey there,
I´ve got a severe problem with my laptop (Windows 7 Home Premium 32bit). Some days ago I got a virus, which Avira knows as "BOO/Alureon.A". It caused some bad things in my boot sector, and after reboot and logging me in, it took approx. 5 minutes until I got to the desktop. The last two minutes I got stuck in blackscreen with my mouse, until the Explorer started. There was also a message that many Windows Services are deactivated. Other softwares, games etc. on my PC were still working. Me and my dad (he´s a real genius in such things) tried some Boot Scan programs, none could fix it.
A bit later we found out, that I have to write my MBR anew, and that I`ve got the necessary installation files from Win7 already on a hidden partition on my Laptop (it´s from Lenovo, by the way). With the Commands "bootrec /fixmbr" and "bootrec /fixboot" I reset my boot sector, now with every start up a short Bluescreen appears:
A problem has been detected and Windows has been shut down to prevent damage to your computer.

If this is the first time you've seen this Stop error screen,
restart your computer. If this screen appears again, follow
these steps:

Check for viruses on your computer. Remove any newly installed
hard drives or hard drive controllers. Check your hard drive to make
sure it is properly configured and terminated.

Run CHKDSK /F to check for hard drive corruption and then
restart your computer.

Technical Information:

*** STOP 0x0000007B (0xF9E49528, 0xC0000034, 0x00000000, 0x00000000)

and then the PC tries to reboot. How it told me, I tried a whole drive scan with "CHKDSK /R", but no success. But after some more scans, we found out, that the virus seems to be deleted.
So is there any way how I can repair my boot sector?
Would be pleasured with quick answers, thank you

Looks good, will try it later, thank you :)

With any infection that serious, you need to wipe the HD to clean reinstall.

SSD / HDD : Optimize for Windows Reinstallation
Clean Install Windows 7

If you must save your files, they should be placed on a DVD or external in quarantine and scanned with Avast or MSE then Malwarebytes.

My father will try it with a Win7-DVD now, the files on my laptop seem not to be working...

The only way to know a serious infection is gone is to wipe the HD to clean reinstall, especially it is still showing symptoms.

Many serious infections are impossible to remove completely.