crashing due to kernal power 41

Hi there, i have a Acer 7535g laptop that I have had for about 6 months now. 3 months ago it started to crash alot, as a result I decided to reformatted thinking i did something wrong on the initial set-up after buying it. However now it has started to show similar problems. The last time I was forced to reformat was due to continuous "kernel power 41 errors", unfortunately the latest crash after reformatting was today and due to the same problem. I have copied the error from the event log and hopefully you will be able to help.
Another issue I have came across was the system restore service. After the initial crash today I was going to try a system restore, oddly it said i had no restore points. this was the same as the last time as well. When I tried to go the service and application section under manage from my computer to find the system restore service it wasn't there. It is even weirder that after I had reformatted I check to see if it was automatic. It was, But now (without touching it) it has turned itself off. hopefully you can shed some light in the issues. Thanks in advance.

Log Name: System
Source: Microsoft-Windows-Kernel-Power
Date: 15/07/2010 21:48:44
Event ID: 41
Task Category: (63)
Level: Critical
Keywords: (2)
User: SYSTEM
Computer: Steven-PC
Description:
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>41</EventID>
<Version>2</Version>
<Level>1</Level>
<Task>63</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000002</Keywords>
<TimeCreated SystemTime="2010-07-15T20:48:44.842829500Z" />
<EventRecordID>44086</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="8" />
<Channel>System</Channel>
<Computer>Steven-PC</Computer>
<Security UserID="S-1-5-18" />
</System>
<EventData>
<Data Name="BugcheckCode">0</Data>
<Data Name="BugcheckParameter1">0x0</Data>
<Data Name="BugcheckParameter2">0x0</Data>
<Data Name="BugcheckParameter3">0x0</Data>
<Data Name="BugcheckParameter4">0x0</Data>
<Data Name="SleepInProgress">false</Data>
<Data Name="PowerButtonTimestamp">0</Data>
</EventData>
</Event>