Consistent BSOD crashes, Various errors, ntoskrnl.dll replaced Help!!

I have a lenovo Thinkpad X1 model number 129126U (a month old) which has consistently been experiencing BSOD events from the day I recieved the machine. Initially these BSOD events were very frequent (approximately 8 to 10 times in a day) however over a period of a month and after 5 to 6 reinstalls, complete set of driver updates and in the course of my last effort two days ago delete and replacement of ntoskrnl.dll and hal.dll drivers using first hand downloaded MS Win 7 Pro 64bit iso installer from digital river and using the official MS forums instructions to copy replace dlls using command prompt the event still continues. I even downloaded and ran the latest memtest86+ and an it for 7 to 8 passes and recieved errors after the 3rd pass till the 7th pass after which I closed the memtest application. I informed the Local Lenovo techincal partner but since the dump files indicated ntoskrnl.dll as prime cause of event was directed by them to reinstall the OS. They also said that the memtest86+ may give false positives so it is appropriate to have confirmation on the OS stability before moving on to the hardware replacement. I have several softwares installed on the system and many hours spent in bringing the maching to an operating status that meets my requirements and do not desire to go over the excersise of reinstalling again as I strongly feel that it may not be the OS drivers that are causing this situation rather a hardware issue. My last effort in copy and replace of the dll was driven out from this The BSOD usually happens after use of the machine of over 6 to 8 hours and may present any type of fault prior to my replacement of the dll files it generlly used to say Memory Management however after the replacement of the dll files it has stated PFN_LIST_COrrupt and SYSTEM_SERVICE _EXCEPTION errors. I am now a stage wherby I either do a complete format of my HDD and reinstall using the downloaded version of the OS and if the event still continues then report and request replacement of memory module. I would appreciate if anyone can help me out of my problem.

Thanks
Jey

Lenovo Thinkpad X1 1291-26U
Intel Core i5 2520M CPU @ 2.50Ghz
4GB DDR3 SDRAM Single Slot
Hitachi HTS723232A7A364 @ 320GB @ 7200RPM
Windows 7 Professional X64 build 7601
Intel HD Grphics
Conexant 20672 Smart Audio HD
Thinkpad Maxbright Display
1366X768

Anyone available on the forums to comment or guide?

Anyone, if no one here can help at least give me advice where to go to for review of the dump files appreciate your input and guidance

regards