Laptop Restarts at bios screen...

Hey Everyone,

Nice to meet u all..... ^_^

I recently bought a Lenovo Ideapad U410 Ultrabook it came with windows 7 64bit and i just wanted to re partition the Harddisk and at tat time i only had windows 7 ultimate 32bit os... so i tried installing it... And when it asks for the partition to install the os it displayed nothing it was empty... And then i read somewhere that we need to change the sata controller mode to AHCI From RAID and i did tat in bios and then tried installing again and everything worked fine but the next day when i tried to turn on the lap it shows the lenovo screen and then it keeps on restarting in a continuous loop.. then i have to turn off the lap and turn it on again and it will work fine then.. this doesn't happen everytime i turn on the system but sometimes.. how can i fix this??? Hope u can help me..

Thanks ^_^