Help Needed, Please.

As my user name suggests, I have a compaq presario 700 and I got the following blue screen error on 7/2:

Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 7/2/2009
Time: 6:32:29 PM
User: N/A
Computer: USER-89D90B88FE
Description:
Error code 00000019, parameter1 00000020, parameter2 e1e2a160, parameter3 e1e2a7a0, parameter4 0cc80208.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 53 79 73 74 65 6d 20 45 System E
0008: 72 72 6f 72 20 20 45 72 rror Er
0010: 72 6f 72 20 63 6f 64 65 ror code
0018: 20 30 30 30 30 30 30 31 0000001
0020: 39 20 20 50 61 72 61 6d 9 Param
0028: 65 74 65 72 73 20 30 30 eters 00
0030: 30 30 30 30 32 30 2c 20 000020,
0038: 65 31 65 32 61 31 36 30 e1e2a160
0040: 2c 20 65 31 65 32 61 37 , e1e2a7
0048: 61 30 2c 20 30 63 63 38 a0, 0cc8
0050: 30 32 30 38 0208

Then yesterday I got this :

Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 7/3/2009
Time: 4:24:23 PM
User: N/A
Computer: USER-89D90B88FE
Description:
Error code 0000004e, parameter1 00000099, parameter2 00000000, parameter3 00000000, parameter4 00000000.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 53 79 73 74 65 6d 20 45 System E
0008: 72 72 6f 72 20 20 45 72 rror Er
0010: 72 6f 72 20 63 6f 64 65 ror code
0018: 20 30 30 30 30 30 30 34 0000004
0020: 65 20 20 50 61 72 61 6d e Param
0028: 65 74 65 72 73 20 30 30 eters 00
0030: 30 30 30 30 39 39 2c 20 000099,
0038: 30 30 30 30 30 30 30 30 00000000
0040: 2c 20 30 30 30 30 30 30 , 000000
0048: 30 30 2c 20 30 30 30 30 00, 0000
0050: 30 30 30 30 0000

Then today this :

BCCode : 10000050 BCP1 : FF8F6066 BCP2: 00000000 BCP3: BF81F9A0
BCP4: 00000000 OSVer: 5_1_2600 SP: 2_0 Product : 768_1

Event Type: Error
Event Source: System Error
Event Category: (102)
Event ID: 1003
Date: 7/4/2009
Time: 4:35:57 PM
User: N/A
Computer: USER-89D90B88FE
Description:
Error code 10000050, parameter1 ff8f6066, parameter2 00000000, parameter3 bf81f9a0, parameter4 00000000.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 53 79 73 74 65 6d 20 45 System E
0008: 72 72 6f 72 20 20 45 72 rror Er
0010: 72 6f 72 20 63 6f 64 65 ror code
0018: 20 31 30 30 30 30 30 35 1000005
0020: 30 20 20 50 61 72 61 6d 0 Param
0028: 65 74 65 72 73 20 66 66 eters ff
0030: 38 66 36 30 36 36 2c 20 8f6066,
0038: 30 30 30 30 30 30 30 30 00000000
0040: 2c 20 62 66 38 31 66 39 , bf81f9
0048: 61 30 2c 20 30 30 30 30 a0, 0000
0050: 30 30 30 30 0000

Any ideas on how to determine what's wrong and how to fix it?