Some times in windows openoffice cannot render malayalam correctly. In such situations do the following …

1. open the particular opeonoffice application such as openofice org or calc etc.

2. Click the menu tools and select options.

3. Then language settings , click language.

4. Then in the right side bottom you can see a check box enabled for complex text layouts(CTL)

5. Now enabled the CTL select box and select malayalam from this select box.

Now you completed the settings and can use malayalam comfortly