Add two matrices

import java.lang.*;
import java.io.*;
class addmatrix
{
static void add()
{
int a[][], b[][], c[][];
a = new int[2][2];
b = new int[2][2];
c = new int[2][2];
DataInputStream dts=new DataInputStream(System.in);
try
{
System.out.println("enter first matrix
2*2 order :");
for(int i=0;i<2;i++)
{
for(int j=0;j<2;j++)
{
a[i][j]=Integer.parseInt(dts.readLine());
}
}
System.out.println("enter second matrix
2*2 order :");
for(int i=0;i<2;i++)
{
for(int j=0;j<2;j++)
{
b[i][j]=Integer.parseInt(dts.readLine());
}
}
for(int i=0;i<2;i++)
{
for(int j=0;j<2;j++)
{
c[i][j]=a[i][j]+b[i][j];
}
}
for(int i=0;i<2;i++)
{
for(int j=0;j<2;j++)
{
System.out.print(c[i][j]+" ");
}
System.out.println("\t");
}
}
catch(Exception x)
{
System.out.println("error");
}
}
public static void main(String arg[])
{
add();
}
}

Change Logon Screen

Now, You can change your logon screen background and also edit your logonui.exe through resource hacker download it from here.
Now, Browse to C:\winnt\system32 or C:\windows\system32 and copy & paste logonui.exe into the same directory. 
It should name the copy: copy of logonui.exe Once you have done that, copy logonui.exe again and paste it to C:\ 
Now, open C:\logonui.exe with Resource hacker. Click on Action and then on Replace bitmap. 
If you are good with graphics you can make your own logon screen, you should be able to scroll thru the bitmaps in this file and figure out what's where.
Once you have everything the way you want it, just save the file to C:\ and close Resource hacker. 
Now, your going to need a Windows 98 bootdisk so you can get in dos mode. 
You can go here and download a bootdisk, if you don't already have one. 
Once at the DOS prompt, you must copy the new logonui.exe file over the existing one. 
Go to the directory where you extracted the new logonui file (C:\logonui.exe) and type: copy logonui.exe c:\windows\system32\ or C:\winnt\system32 on some systems. 
It will ask if you want to overwrite the file, just say yes. 
All done! Once you reboot you should see your new logon screen. 
If for some reason you screwup, go back in dos and copy the copy of logonui.exe file and replace it with the one in C:\winnt\system32 or C:\windows\system32.

Who Used Your Pc In Your Absence,what Did He Do?

first you should go
start > run >eventvwr.msc
Events are stored in three log files: Application, Security, and System. These logs can be reviewed and archived.
For our purposes we want the System log. Click on "System" in the left-hand column for a list of events.
Look for a date and time when you weren't home and your computer should have been off.
double click on the eg: info n it will show u the detail.
You can also use this log to see how long someone was on the computer. Just look at the time the computer was turned on and off for that day.