Microsoft ends support for Windows XP today, and Google is using the opportunity to promote Chrome OS as a replacement. Its offering a number of discounts on its Chromebooks for Business program today through the end of June in the hopes that businesses finally being forced to switch away from the classic operating system will look to Chromebooks instead of PCs to replace them. Its a small gesture by Google — just a $100 or so discount — but it underscores the continuing battle between it and Microsoft, which has been using its Scroogled campaign to malign Chromebooks, among other Google products. Googles simple OS is familiar to anyone whos used Chrome before, and it runs well on inexpensive hardware — just what businesses might be looking for to replace their old PCs and laptops.