There is no need to reinstall if you couldn't get back into run level 5. Just reboot the machine. If it still wont load into run level 5 then /etc/inittab so as the line

id:x:initdefault

is reading to run level 5 when booting. Where x is make that a 5 if it already isn't. You can change to whatever runlevel you want to from editing the /etc/inittab file to the run level you want.

here is a copy of something I found on the web for the run levels.

Runlevel Meaning
0 System halt
S Single user mode; from boot prompt with US keyboard layout 1 Single user mode
2 Local multiuser without remote network (standard)
3 Full multiuser with network
4 Unused
5 Full multiuser mode with network and xdm
6 System reboot

Or you can go to THIS to find out more information about what you are doing.